Guard for insulating booms

ABSTRACT

An insulated guard particularly adapted for use on telescopic crane booms as either initial installation or conversion equipment; the guard consisting of a skeletonized framework electrically insulated from the extensible portion of a boom and including means substantially balancing the guard at the terminal end of the boom and providing an essentially resilient or shock absorbing assembly to minimize fracturing of the cooperating elements, and including an improved mounting assembly minimizing the fasteners in number and complexity to enable relatively unskilled labor to maintain and repair the equipment.

United States Patent Grasby [54] GUARD FOR INSULATING BOOMS [72] Inventor: James L. Grasby, Little Rock, Ark.

[73] Assignee: Saf-T-Boom Corporation, Little Rock,

Ark.

[22] Filed: Dec. 7, 1970 [21] Appl. No.: 95,716

[52] U.S.Cl ..212/l, 174/5 [5 1] Int. Cl. ..B66c 15/00 [58] Field of Search ..2l2/l, 39; 174/5, 5 80; 182/46 [56] References Cited UNITED STATES PATENTS 2,950,016 8/1960 Thomas ..2l2/l 2,989,194 6/1961 Thomas [4 1 Apr. 4, 1972 3,100,575 8/1963 Coffey ..2l2/l Primary Examiner-Harvey C. Hornsby Assistant Examiner-Merle F. Maffei Attorney-Samuel Meerkreebs ABSTRACT An insulated guard particularly adapted for use on telescopic crane booms as either initial installation or conversion equipment; the guard consisting of a skeletonized framework electrically insulated from the extensible portion of a boom and including means substantially balancing the guard at the terminal end of the boom and providing an essentially resilient or shock absorbing assembly to minimize fracturing of the cooperating elements, and including an improved mounting assembly minimizing the fasteners in number and complexity to enable relatively unskilled labor to maintain and repair the equipment.

8 Claims, 5 Drawing Figures PATENTED APR 4 I972 INVEHTOR JAMES L GRASBY ATTOR NE Y GUARD FOR INSULATING BOOMS BACKGROUND 1. Field of the Invention The invention generally related to insulating apparatus and more particularly to a safety device or guard adapted for use on the terminal end of a boom of a crane or on well drilling equipment as well as on the extendable portion of telescopic booms etc.

2. Prior Art This invention is particularly directed to an improved boom guard of the character disclosed in US Letters Pat. Nos. to Thomas, 2,950,016 and 2,989,194.

BRIEF SUMMARY OF THE INVENTION The invention primarily is in means whereby boom guards of the general character disclosed in the prior art include an improved mounting means and the guard is substantially balanced on the terminal end of a boom (particularly adapted for an extendable section of telescopic type); the improved mounting incorporating a minimum number of fasteners and of a relatively simple character whereby unskilled labor can maintain, repair and instal the guard; the guard and mounting providing an unusual balance and strength as well as an unusual simplicity in construction.

Other objects and the more specific nature of the invention will become apparent from the following description when taken with the drawing forming a part thereof, wherein:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of the terminal end ofa telescopic boom showing an insulating guard incorporating the invention, and showing the extendable section of the boom (with the guard mounted thereon) extended in phantom lines;

FIG. 2 is an enlarged end elevation looking from right to left at FIG. 1;

FIG. 3 is a vertical section taken on the plane ofline 33 of FIG. 1 with a portion broken away and sectioned;

FIG. 4 is a fragmentary section taken on the plane of line 4-4 of FIG. 2; and

FIG. 5 is a fragmentary perspective view of the boom guard of the invention with intermediate portions broken away.

DETAILED DESCRIPTION OF THE INVENTION The prior art patents to Thomas set forth in detail the problems and successful solutions in the art.

In its broadest aspect, just as in the Thomas patents, the present invention contemplates a guard for crane booms for preventing short circuiting of electrical lines against which the boom might accidentally contact and thus preventing current from being conducted through the boom to the crane operator.

As is illustrated in greater detail in FIG. 7 of the patent to Thomas, in FIG. 1 there is shown a fragmentary forward portion of a crane boom 10 which includes one or more extensible sections 12. The extensible section 12 may be operated, or extended and retracted in any suitable manner, i.e., hydraulically, for example, not shown. The boom section 12 will include a conventional hookand cable assembly 14, for example, and removably mounted on the forward end of section 12 is an insulating guard 16 for preventing current transmittal through the guard to the boom and ultimately to the crane operator.

The guard includes preferably insulation coated side rods 18 and 20 as well as a top rod 22 parallel thereto. The side rods 18 and 20 are connected at the forward end by an integral, semi-circular bight of guard portion The the longitudinal elements 18-24 are suitably welded to longitudinally spaced frame elements 26, 28, 30 and 32; the first three elements from the rear of the guard, forwardly, are substantially semi-circular or slightly greater than a span of 180; see FIG. 3 for example, and the forwardmost element 32 is circular; see

FIGS. 2 and 5. The four frame elements 26-32 is an arbitrary number found to be practical in the field, however, this is merely illustrative. Extending diametrically from the forward end of the top rod 22 and diametrically from the top center of element 32 to the lower portion thereof are a pair of semi-circular, suitably welded elements 34,36 which are intermediately welded to central portions of the transverse bight portion 24; see FIGS. 2 and 5.

Extending in chordal relation and welded to elements 28 and 30 are transverse support elements 38 and 40, respectively, the latter including a vertical brace 42 disposed between the elements 34 and 36; see FIG. 5. Secured by tubular mounting sleeves on the support elements 38 and 40 are spaced pairs of insulators 44,46 and 48,50 respectively. The insulators 44-50 are suitably rated to withstand current transmittal over and beyond that conventionally found in high-tension current transmittal systems with a factor of safety that insures that the insulators will not break down when subject to currents accidentally encountered by a boom guard on a boom of the character involved.

The insulators 46,48 are suitably secured at the lower ends to intermediate portions of mounting rods 52 and 54 respectively, disposed inwardly of and parallel to the respective side rods 18 and 20. The mounting rods 52 and 54 include at the forward terminal end apertured mounting pads 56 and 58 respectively, which receive therethrough studs or bolts 60,62. Depending from the mounting rods 52,54 rearwardly of the mounting pads are angular-sub-mounting rods 64,66 respectively, which have at the lower terminal end apertured mounting pads 68 and 70, respectively, generally immediately below and in alignment with the pads 60,62. The mounting pads 68,70 will receive studs or bolts 72; 74 respectively, to mount the guard on the opposite sides of the extensible section 12 of the boom.

The forward insulators 48,50-are secured at the lower ends to a mounting-nose assembly comprising a horizontal plate 76 which are suitably secured to its under surface legs 78 or a transverse, vertical nose-engaging plate 80 which is apertured to receive bolts or studs 82; see FIGS. 2 and 4, which extends longitudinally from the terminal end of section 12.

The boom guard, contrary to that of the prior art, is mounted on the extensible section 12 by means of 6 cooperating bolts or studs; two on each side of section 12, i.e., see 62, 74 and 60,72, and two at the distal end; see 82. The mounting and removal of the guard is accomplished readily and by relatively unskilled labor, and the wear on the boom guard is negligible, i.e., there are no moving part or rollers riding on moving cables, for example, as seen in the prior art.

Additionally, the portion of the guard rearwardly of the mounting pad substantially counter-balances that portion forward of the pads; the maximum strength elements reinforcing the nose portion of the guard to absorb blows, and the rear skeletonized rods having an inherent resiliency due to the cantilever support to absorb shocks in the event the guard is raised into current conductors.

What is claim ed is:

1. For use on a boom having a movable section, a guard for preventing said boom from a power line,

said guard comprising an elongated frame having portions for extending in protecting relation over the top side and end ofa boom, and

insulated mounting means on said frame for mounting said frame on said guard,

the improvement wherein:

said mounting means including a pair of elongated rods extending longitudinally in mutually parallel relation inside said guard, a mounting pad at the forward end of said rods, and sub-mounting rods depending from said rods and including a second mounting pad generally beneath said first mentioned mounting pad.

2. The structure as claimed in claim 1 including a pair of insulators depending from an intermediate portion of said guard and being secured to said rods rearwardly of said mounting pads.

3. The structure as claimed in claim 1 including a forward pair of depending insulators, and a mounting-nose assembly extending transversely beneath said insulators, and including a vertical nose-plate for connection to the forward end of the boom section.

4. The structure as claimed in claim 3 in which said mounting pads and plates are vertically disposed, said mounting pads and plates including means for removable securement to the front and sides of the boom section.

5. The structure as claimed in claim 1 in which said guard and rods are cantilever supported rearwardly of said mounting plates.

6. The structure as claimed in claim 5 including a pair of insulators depending from an intermediate portion of said guard and being secured to said rods rearwardly of said mounting pads. 4

7. The structure as claimed in claim 6 including a forward pair of depending insulators, and a mounting-nose assembly 

1. For use on a boom having a movable section, a guard for preventing said boom from a power line, said guard comprising an elongated frame having portions for extending in protecting relation over the top side and end of a boom, and insulated mounting means on said frame for mounting said frame on said guard, the improvement wherein: said mounting means including a pair of elongated rods extending longitudinally in mutually parallel relation inside said guard, a mounting pad at the forward end of said rods, and submounting rods depending from said rods and including a second mounting pad generally beneath said first mentioned mounting pad.
 2. The structure as claimed in claim 1 including a pair of insulators depending from an intermediate portion of said guard and being secured to said rods rearwardly of said mounting pads.
 3. The structure as claimed in claim 1 including a forward pair of depending insulators, and a mounting-nose assembly extending transversely beneath said insulators, and including a vertical nose-plate for connection to the forward end of the boom section.
 4. The structure as claimed in claim 3 in which said mounting pads and plates are vertically disposed, said mounting pads and plates including means for removable securement to the front and sides of the boom section.
 5. The structure as claimed in claim 1 in which said guard and rods are cantilever supported rearwardly of said mounting plates.
 6. The structure as claimed in claim 5 including a pair of insulators depending from an intermediate portion of said guard and being secured to said rods rearwardly of said mounting pads.
 7. The structure as claimed in claim 6 including a forward pair of depending insulators, and a mounting-nose assembly extending transversely beneath said insulators, and including a vertical nose-plate for connection to the forward end of the boom section. The structure as claimed in claim 7 in which said mounting pads and plates are vertically disposed, said mounting pads and plates including means for removable securement to the front and sides of the boom section. 